I made quicky mozz this weekend (3 gal fresh goats milk). Mozzarella turned out good, and I got a good yield of ricotta from the whey (about 1 lb).

Used citric acid, lipase and rennet for the mozz. Brought the whey up to 200 degrees, added about 3/4 cup vinegar, stirred it in, and then let it cool a bit before draining. The ricotta looks beautiful, but it tastes a bit sour, a bit like milk that's gone off (or if you've had some reflux after drinking milk ).

Also, my ricotta comes out absolutely creamy. I don't know if that's right or not.

I make goat milk ricotta regularly. If the whey is fresh it is beautiful.

For 20L of whey I use only 200ml of white vinegar. Although as said previously if you have already added citric acid you may be able to reduce this amount.

The trick is not to add any acidulant until it reaches 85oC. Add, stir briefly then let stand for a few minutes.

If the whey has already contains sufficient acid the ricotta will form spontaneously as you heat it. In this case you don't need to add vinegar, or use less. I use the colour of the whey as a guide - if it is transparent then its done. If it is still milking add a bit more vinegar to precipitate out the remaining solids.

I don’t add any acid such as vinegar to my ricotta. I use goat whey that has been made with a mesophyllic culture. (Different than the mozz you are working with.) I just put the whey back into the empty cheese pot after draining the curds, then slowly bring it up to *just* a rolling boil. The curd mass floats to the top when it gets hot and can be drained then for a creamier cheese, but I found that letting it boil just slightly before ladling off the curds makes for a “fluffier” and drier soft cheese that is more like a cream cheese spread in texture and very good. Because of the boiling, the curd mass is in clumps rather than whole, but still floating and just as easy to ladle out.

After doing it this way for a couple of years I wonder why vinegar is ever called for at all. It may help get the last little bit of solids out of the whey, but it adds that sour taste you mentioned. I get whatever curds I am going to get with heating alone and then fertilize the garden with the rest of the whey. I have never had trouble getting a curd once the whey gets hot enough. I am also thinking that the lipase in the whey you were using would have also added its own bit of flavor to the ricotta, perhaps making it less mild tasting.